Transfer vessel apparatus and method of storing samples

Abstract

A transfer vessel apparatus has a device for introducing gas from a liquid nitrogen trap into a vessel body to form and maintain an inert atmosphere in the vessel body. The inert atmosphere maintained in the vessel body enables a sample to be stored for long periods and enables transfer of the sample between different vacuum systems.

What is claimed is: 
     
       1. A transfer vessel apparatus comprising: a hermetic vessel for housing a sample;   means for detachably connecting the hermetic vessel to a vacuum system;   a heat insulated vessel containing a cooling medium;   a sample cooling member disposed within the hermetic vessel and having a portion extending into the heat insulated vessel and establishing thermal communication between the sample cooling member and the cooling medium; and   means for introducing gas generated in the heat insulated vessel by evaporation of the cooling medium into the hermetic vessel.   
     
     
       2. A transfer vessel apparatus according to claim 1 wherein the cooling medium comprises liquid nitrogen. 
     
     
       3. An apparatus as claimed in claim 1 wherein the means for introducing gas comprises: means for defining a first flow path connected to the hermetic vessel and a second flow path;   valve means for selectively connecting the heat insulated vessel to one of the flow paths.   
     
     
       4. An apparatus as claimed in claim 3 wherein the second flow path communicates with the outside of the apparatus. 
     
     
       5. A transfer vessel apparatus comprising: a hermetic vessel for housing a sample;   means for detachably connecting the hermetic vessel to a vacuum system;   a heat insulated vessel containing a cooling medium;   a sample cooling member disposed within the hermetic vessel and having a portion extending into the heat insulated vessel and establishing thermal communication between the sample cooling member and the cooling medium; and   means for introducing an inert gas into the hermetic vessel.   
     
     
       6. A transfer vessel apparatus according to claim 5 wherein the inert gas is selected from the group consisting of nitrogen gas, argon gas, and helium gas. 
     
     
       7. A method of storing a sample using a transfer vessel apparatus comprising: hermetically connecting a hermetic vessel to a vacuum system;   moving a sample from the vacuum system into the hermetic vessel;   disposing a thermal conductor in the hermetic vessel and around the sample;   cooling the thermal conductor with a cooling medium disposed in a heat insulated vessel disposed outside the hermetic vessel; and   introducing gas generated by evaporation of the cooling medium in the heat insulated vessel into the hermetic vessel.   
     
     
       8. A method as claimed in claim 7 wherein introducing the gas comprises creating a gas pressure in the hermetic vessel greater than or equal to the ambient pressure on the outside of the hermetic vessel. 
     
     
       9. A method as claimed in claim 7 further comprising releasing gas generated by evaporation of the cooling medium in the heat insulated vessel to the outside of the apparatus.